How to Seal Threads on Galvanized Pipe

Galvanized metal piping is coated with zinc in order to prevent corrosion. Before assembling the pipes, further insulation is required to avoid leakage and friction that could contaminate a system. This can be achieved by use of a sealant intended for the galvanized pipe threads. TFE pipe tape combined with an anaerobic sealant will provide the most effective bond between male and female pipe threads. These sealants are airtight, water-resistant and do not require any special tools for installation.

Things You'll Need

• TFE pipe tape
• Anaerobic pipe dope
• Dry rag

Instructions

1. Select a TFE tape based on density and thickness. The most often-recommended teflon tape has a 3 to 4mm thickness and a density of 1g per CC.

2. Wrap the tape in the direction of the male thread spiral, starting with the first two threads. Do not let the tape overhang the first thread, or it could create space for contaminants that may disrupt the piping system.

3. Draw the loose end of the tape tightly around the threads. Use your thumbnail to press the tape into threads so it conforms to the surface.

4. Ensure that the exposed side of the tape is free from any residue. Pipe dope, or sealant, is most effective without foreign elements that could trap air.

5. Squeeze the anaerobic sealant in a full 360-degree bead around the first two male threads. Carefully assemble the male and female galvanized pipes and use a dry rag to wipe away the excess sealant.

References

• Swagelok: PTFE Pipe Sealant
• Pipe Joint Thread Sealant Instructions